Sharing a collection with a Community in Edelweiss+ is really simple. (*Publisher users see note at bottom of page!)
Go to the Catalog tab of your account. On the left side of the page, you will see Catalog Options. Click on My Collections, to view your collections. Choose a collection to share and click the Share Collection icon located on the bottom right corner of the collection lane:
In the window that opens up, tick the box next to Communities and then click on the elipses to the right:
A new window will open up which will display the Communities that you have joined with which you can share the collection. Tick the boxes next to each Community you wish to share your collection with, then click Continue. To de-select the Community, tick the box again:
You will be taken back to the previous window. Click the save icon on the bottom right corner of the window and your collection has been shared!
*Note that publisher users share collections in a different and more formal way, sharing them just like they share Markups. Details specific to publisher users and Collection Sharing can be found here.